Comparison of intestinal parasitic infection in newly arrived and resident workers in Qatar

Background: The rapid growth of Qatar in the last two decades has been associated with an enormous expansion of building programs in its cities and in the provision of new service industries. This in turn has attracted a large influx of immigrant workers seeking employment in jobs associated with food handling, domestic service and the building industry. Many of these immigrants come from countries in the tropics and subtropics where intestinal parasitic infections are common. Methods: We analyzed intestinal parasitic infections recorded in 2008 among immigrant and long-term resident workers in Doha city, Qatar (n = 1538). Stool examinations were carried out at the Hamad Medical Corporation and at the Medical Commission in Doha using standard procedures. Results: Overall, 21.5% of subjects were infected with at least one of the species recorded (8 helminth and 4 protozoan species; the highest prevalence was for hookworms = 8.3%) and there were strong regional effects on prevalence of helminths, with subjects from North East Africa and Nepal showing particularly high prevalence. Most helminths declined in prevalence in subjects that acquired residency status in Qatar, especially among female subjects, but there was a marked exception among male Nepalese workers, who continued to harbour helminth infections (notably hookworms) after they became residents. Contrary to all other regional groups the prevalence of Giardia duodenalis was higher among Nepalese residents compared with new arrivals, while Blastocystis hominis infections were more common among residents of all regions, and especially among North East Africans. Conclusions: Our analysis has identified male Nepalese workers as a particular risk group continuing to harbour hookworm infection and G. duodenalis as residents, and subjects from North East Africa are as particularly likely to acquire B. hominis infection after settling in the country. These conclusions have important implications for the health authorities in Qatar.